$${{\left({{\mathtt{3}}}^{{\mathtt{3}}}\right)}}^{{\mathtt{3}}} = {\mathtt{19\,683}}$$
$${{\mathtt{3}}}^{{\mathtt{27}}} = {\mathtt{7\,625\,597\,484\,987}}$$
Because in 3^3^3, you multiply 3*3*3=27
Then you multiply 27*27*27=19 683
3^27 is 3 times itself 27 times with no break